package cn.orange.ch10_dynamicprogramming;

/**
 * LC516.最长回文子序列
 */
public class LC516 {
    public int longestPalindromeSubseq(String s) {
        int n = s.length();
        //dp[i][j]:在s中[i,j]范围内的最长回文子序列长度为dp[i][j]
        int[][] dp = new int[n][n];
        for (int i = 0; i < n; i++) {
            dp[i][i] = 1;
        }
        for (int i = n - 1; i >= 0; i--) {
            for (int j = i + 1; j < n; j++) {
                if (s.charAt(i) == s.charAt(j)) {
                    dp[i][j] = 2 + dp[i + 1][j - 1];
                } else {
                    dp[i][j] = Math.max(dp[i + 1][j], dp[i][j - 1]);
                }
            }
        }
        return dp[0][n - 1];
    }

    public static void main(String[] args) {
        LC516 alg = new LC516();
        System.out.println(alg.longestPalindromeSubseq("bbbab"));
        System.out.println(alg.longestPalindromeSubseq("cbbd"));
    }
}
